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Fluctuations
Kinds of Fluctuations Terms modified by Fluctuations Selected AbstractsTHE FLUCTUATIONS OF ITALIAN GLACIERS DURING THE LAST CENTURY: A CONTRIBUTION TO KNOWLEDGE ABOUT ALPINE GLACIER CHANGESGEOGRAFISKA ANNALER SERIES A: PHYSICAL GEOGRAPHY, Issue 3 2007MICHELE CITTERIO ABSTRACT. This paper describes the recent evolution of Italian glaciers through an analysis of all available terminus fluctuation data that the authors have entered in a glaciers database (named GLAD) containing 883 records collected on glaciers from 1908 to 2002. Furthermore, a representative subset of data (249 glaciers located in Lombardy) was analysed regarding surface area changes. For the analysis of terminus fluctuations, the glaciers were sorted by size classes according to length. The data showed that during the 20th century Italian Alpine glaciers underwent a generalized retreat, with one distinct and well documented readvance episode that occurred between the 1970s and mid-1980s, and a poorly documented one around the early 1920s. The rates of terminus advance and retreat have changed without significant delays for the larger glaciers with respect to the smaller ones. However, the smaller the glacier, the more limited the advance (if any) during the 1970s and early 1980s. The behaviour of glaciers shorter than 1 km appears to have changed in the last decade, and between 1993 and 2002 they retreated at a very high rate. The analysis of the subset of data led to a quanti-fication of surface reduction of c. 10% from 1992 to 1999 for glaciers in Lombardy. Small glaciers proved to contribute strongly to total area loss: in 1999, 232 glaciers (c. 90% of the total) were smaller than 1 km2, covering 27.2 km2 (less than 30% of the total area), but accounted for 58% of the total loss in area (they had lost 7.4 km2). [source] BANK CAPITAL REQUIREMENTS, BUSINESS CYCLE FLUCTUATIONS AND THE BASEL ACCORDS: A SYNTHESISJOURNAL OF ECONOMIC SURVEYS, Issue 5 2009Ines Drumond Abstract In order to survey the mechanisms through which the introduction of Basel II bank capital requirements is likely to accentuate the procyclical tendencies of banking, this paper brings together the theoretical literature on the bank capital channel of propagation of exogenous shocks and the literature on the regulatory framework of capital requirements under the Basel Accords. We conclude that the theoretical models that revisit the bank capital channel under the new accord generally support the Basel II procyclicality hypothesis and that the magnitude of the procyclical effects essentially depends on (i) the composition of banks' asset portfolios, (ii) the approach adopted by banks to compute their minimum capital requirements, (iii) the nature of the rating system used by banks, (iv) the view adopted concerning how credit risk evolves through time, (v) the capital buffers over the regulatory minimum held by the banking institutions, (vi) the improvements in credit risk management and (vii) the supervisor and market intervention under Basel II. The recent events and instability in financial markets all over the world have led the procyclicality issue to enter the agendas of several political international,fora,and some measures to mitigate procyclicality are being put forward. The bank capital channel literature should now play an important role in evaluating their effectiveness. [source] CAPITAL,LABOUR SUBSTITUTION AND ENDOGENOUS FLUCTUATIONS: A MONOPOLISTIC COMPETITION APPROACH WITH VARIABLE MARKUP,THE JAPANESE ECONOMIC REVIEW, Issue 3 2009THOMAS SEEGMULLER This paper analyses an overlapping generations model with endogenous product diversity where strategic interactions between producers are introduced; it examines how they affect the stability properties of the steady state. Because of free entry, strategic interactions between producers imply a new dynamic feature, markup variability, promoting indeterminacy and endogenous cycles. Indeed, in contrast to the model without strategic interaction, endogenous fluctuations can occur when the substitution between the production factors, capital and labour, is not too weak, but in accordance with empirical estimates. [source] SOURCES OF REAL EXCHANGE RATE FLUCTUATIONS: EMPIRICAL EVIDENCE FROM NINE AFRICAN COUNTRIESTHE MANCHESTER SCHOOL, Issue 2009A. H. AHMAD We investigate the sources of real exchange rate fluctuations in a sample of nine African countries from 1980:01 to 2005:04, using a trivariate structural vector autoregression. The analysis is motivated by a stochastic sticky-price model from which three shocks are identified; demand, supply and monetary shocks. The results indicate that demand shocks are the predominant source of real exchange rate movements in these countries, although nominal shocks have also played a small but significant role in South Africa and Botswana, and supply shocks seem to be of some relevance for Algeria, Egypt and Tanzania. [source] Fluctuation of chromatin unfolding associated with variation in the level of gene expressionGENES TO CELLS, Issue 7 2004Noriko Sato We examined whether spontaneous alteration of chromatin structure, if any, correlates with variation in gene expression. Gene activation is associated with changes in chromatin structure at different levels. Large-scale chromatin unfolding is one such change detectable under the light microscope. We established cell clones carrying tandem repeats (more than 50 copies spanning several hundred kb) of the GFP (green fluorescent protein)-ASK reporter genes driven by a tetracycline responsive promoter. These clones constitutively express the transcriptional transactivator. Flow cytometry and live-recording fluorescence microscopy revealed that, although fully activated by a saturating amount of doxycycline, GFP-ASK expression fluctuated in individual cell clones, regardless of the cell cycle stage. The GFP-ASK expression changed from lower to higher levels and vice versa within a few cell cycles. Furthermore, the levels of GFP-ASK expression were correlated with the degrees of chromatin unfolding of the integrated array as detected by FISH (fluorescent in situ hybridization). The chromatin unfolding was not coupled to a mitotic event; around one-third of the daughter-pairs exhibited dissimilar degrees of chromatin unfolding. We concluded that fluctuation of chromatin unfolding was likely to result in variation in gene expression, although the source of the fluctuation of chromatin unfolding remains to be studied. [source] Strain-dependent viral dynamics and virus-cell interactions in a novel in vitro system supporting the life cycle of blood-borne hepatitis C virus,HEPATOLOGY, Issue 3 2009Hussein Hassan Aly We developed an in vitro system that can be used for the study of the life cycle of a wide variety of blood-borne hepatitis C viruses (HCV) from various patients using a three-dimensional hollow fiber culture system and an immortalized primary human hepatocyte (HuS-E/2) cell line. Unlike the conventional two-dimensional culture, this system not only enhanced the infectivity of blood-borne HCV but also supported its long-term proliferation and the production of infectious virus particles. Both sucrose gradient fractionation and electron microscopy examination showed that the produced virus-like particles are within a similar fraction and size range to those previously reported. Infection with different HCV strains showed strain-dependent different patterns of HCV proliferation and particle production. Fluctuation of virus proliferation and particle production was found during prolonged culture and was found to be associated with change in the major replicating virus strain. Induction of cellular apoptosis was only found when strains of HCV-2a genotype were used for infection. Interferon-alpha stimulation also varied among different strains of HCV-1b genotypes tested in this study. Conclusion: These results suggest that this in vitro infection system can reproduce strain-dependent events reflecting viral dynamics and virus-cell interactions at the early phase of blood-borne HCV infection, and that this system can allow the development of new anti-HCV strategies specific to various HCV strains. (HEPATOLOGY 2009.) [source] Spectral decomposition of periodic ground water fluctuation in a coastal aquiferHYDROLOGICAL PROCESSES, Issue 12 2008David Ching-Fang Shih Abstract This research accomplished by the descriptive statistics and spectral analysis of six kinds of time series data gives a complete assessment of periodic fluctuation in significant constituents for the Huakang Shan earthquake monitoring site. Spectral analysis and bandpass filtering techniques are demonstrated to accurately analyse the significant component. Variation in relative ground water heads with a period of 12·6 h is found to be highly related to seawater level fluctuation. Time lag is estimated about 3·78 h. Based on these phenomena, the coastal aquifer formed in an unconsolidated formation can be affected by the nearby seawater body for the semi-diurnal component. Fluctuation in piezometric heads is found to correspond at a rate of 1000 m h,1. Atmospheric pressure presents the significant components at periods of 10·8 h and 7·2 h in a quite different type, compared to relative ground water head and seawater level. Copyright © 2008 John Wiley & Sons, Ltd. [source] Bone Loss, Weight Loss, and Weight Fluctuation Predict Mortality Risk in Elderly Men and WomenJOURNAL OF BONE AND MINERAL RESEARCH, Issue 8 2007Nguyen D Nguyen Abstract Low baseline BMD, rate of BMD loss, weight loss, and weight fluctuation are significant predictors of all-cause mortality in elderly men and women, independent of each other and of age, incident fracture, and concomitant diseases. Introduction: Although low BMD has been shown to be associated with mortality in women, the effect of BMD is affected by weight and weight change and the contribution of these factors to mortality risk, particularly in men, is not known. This study examined the association between baseline BMD, rate of bone loss, weight loss, and weight fluctuation and all-cause mortality risk in elderly men and women. Materials and Methods: Data from 1059 women and 644 men, ,60 years of age (as of 1989), of white background who participated in the Dubbo Osteoporosis Epidemiology Study were analyzed. All-cause mortality was recorded annually between 1989 and 2004. BMD at the femoral neck was measured by DXA (GE-LUNAR) at baseline and at approximately every 2 yr afterward. Data on incident osteoporotic fractures and concomitant diseases, including cardiovascular diseases, all types of cancer, and type I/II diabetes mellitus, was also recorded. Results: In the multivariable Cox's proportional hazards model with adjustment for age, incident fractures, and concomitant diseases, the following variables were independent risk factors of all-cause mortality in men: rate of BMD loss of at least 1%/yr, rate of weight loss of at least 1%/yr, and weight fluctuation (defined by the CV) of at least 3%. In women, in addition to the significant factors observed in men, lower baseline BMD was also an independent risk factor of mortality. In both sexes, baseline weight was not an independent and significant predictor of mortality risk. Approximately 36% and 22% of deaths in women and men, respectively, were attributable to the four risk factors. Conclusions: These data suggest that, although low BMD was a risk factor of mortality in women, it was not a risk factor of mortality in men. However, high rates of BMD loss, weight loss, and weight fluctuation were also independent predictors of all-cause mortality in elderly men and women, independent of age, incident fracture, and concomitant diseases. [source] Fluctuation in Autonomic Tone is a Major Determinant of Sustained Atrial Arrhythmias in Patients with Focal Ectopy Originating from the Pulmonary VeinsJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 3 2001MARC ZIMMERMANN M.D. Autonomic Variations in Focal AF. Introduction: This study was designed to analyze dynamic changes in autonomic tone preceding the onset of sustained atrial arrhythmias in patients with focal atrial fibrillation (AF) to determine why patients with frequent discharge from the arrhythmogenic foci develop sustained AF. Methods and Results: Holter tapes from 13 patients (10 men and 3 women; mean age 53 ± 5 years) with paroxysmal "lone" AF (mean 18 ± 13 episodes per week) and a proven focal origin (pulmonary veins in all cases) were analyzed. A total of 38 episodes of sustained AF (> 30 min) were recorded and submitted to frequency-domain heart rate variability analysis. Six periods were studied using repeated measures analysis of variance: the 24,hour period, the hour preceding AF, and the 20 minutes before AF divided into four 5,minute periods. A significant increase in high-frequency (HF, HF-NU) components was observed during the 20 minutes preceding AF (P = 0.003 and 0.002, respectively), together with a progressive decrease in normalized low-frequency (LF-NU) components (P = 0.035). An increase in LF/HF ratio followed by a linear decrease starting 15 minutes before sustained AF also was observed, indicating fluctuations in autonomic tone, with a primary increase in adrenergic drive followed by a marked modulation toward vagal predominance immediately before AF onset. Conclusion: In patients with focal ectopy originating from the pulmonary veins, sustained episodes of atrial arrhythmias are mainly dependent on variations of autonomic tone, with a significant shift toward vagal predominance before AF onset. [source] Fluctuation of Vegetative Storage Proteins in the Seedlings of Swietenia macrophylla, Analogous to the Seasonal Changes of Those in the Shoot of the Adult TreeJOURNAL OF INTEGRATIVE PLANT BIOLOGY, Issue 3 2007Ya-Qin Han Abstract In order to identify appropriate plant materials for studying the gene expression and biological function of vegetative storage proteins (VSPs) in woody plants, the VSPs in the seedlings of Swietenia macrophylla King were investigated by using light microscopy, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western-blotting. The seed of S. macrophylla was rich in storage proteins that accumulated in the vacuoles of cotyledon parenchyma cells in appearance of compact spherical grains. The growth and development of S. macrophylla seedlings were characterized by an obvious growth rhythm. The storage proteins in seeds disappeared during seedling growth while VSPs appeared in the stem 2 weeks after seedling leaves matured. Thereafter, the VSPs in the seedling stem almost exhausted during new shoot growth, and when the leaves of new shoot just matured, both the stem beneath the new shoot of seedlings and the stem of new shoot started to accumulate VSPs. Nitrogen application dramatically increased the level of VSPs, but had little influence on the dynamics of VSP consumption and accumulation in seedling stem. Together with these data, the fluctuation of VSPs in seedlings was very similar to that in the branches of the adult trees. In addition, seedlings are easy to be treated due to their small size. Our results suggested that S. macrophylla seedlings were suitable for investigating the biological roles of VSPs and the mechanism of nitrogen storage in trees. [source] Fluctuation of gastrointestinal symptoms in the community: a 10-year longitudinal follow-up studyALIMENTARY PHARMACOLOGY & THERAPEUTICS, Issue 8 2008A. C. FORD Summary Background, There are few studies examining the stability of gastrointestinal symptoms during prolonged periods of follow-up. Aim, To examine this issue in individuals previously recruited into a community screening programme for Helicobacter pylori providing symptom data at study entry. Methods, All traceable participants were sent dyspepsia and IBS questionnaires by post at 10 years. Symptom subgroups were assigned at baseline and 10-year follow-up. Individuals symptomatic at both time points who changed subgroup were compared with those symptomatic and remaining in the same subgroup. Results, Three-thousand eight hundred and nineteen individuals provided data. At baseline, 2417 (63%) were asymptomatic or did not meet diagnostic criteria for a subgroup. Of these, 1648 (68%) remained asymptomatic at 10 years, whilst 769 (32%) reported symptoms. Of the 1402 individuals symptomatic at baseline, 404 (29%) remained in the same subgroup at 10 years, 603 (43%) changed subgroup and symptoms resolved or did not meet criteria for a subgroup in 395 (28%). Symptom stability was more likely in males [odds ratio (OR): 1.50; 99% confidence interval (CI): 0.97,2.31] and older subjects (OR per year: 1.09; 99% CI: 1.01,1.17). Conclusion, Of those subjects symptomatic at baseline, almost three-quarters remained symptomatic at 10 years, but over 40% changed symptom subgroup. [source] Impact of the delay ripple of cascaded gratings on dispersion compensation of long-haul fiber transmission systemsMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 2 2004Tigang Ning Abstract Delay ripples of chirped-fiber Bragg grating (CFBG), which can compensate 200-km-long fiber's dispersion, is detailedly analyzed. A numerical simulation of the delay ripple of cascaded gratings is done using Schrödinger's equation and is compared with an experiment using a 1000-km transmission system over G.652 fiber by five groups of CFBGs for dispersion compensation. The research shows that the system degradation depends on the delay-ripple period, which is 0.01,0.1 nm, and its amplitude. Fluctuation of the power penalty, which depends on the CFBG's ripple period when the source wavelength is changed ±20 GHz around the CFBG's center wavelength, is experimentally studied. The theoretical results agree well with the experimental results. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 42: 100,102, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20220 [source] Fluctuation in self-perceived stress and increased risk of flare in patients with lupus nephritis carrying the serotonin receptor 1A ,1019 G alleleARTHRITIS & RHEUMATISM, Issue 10 2006Daniel J. Birmingham Objective Stress is believed to be a risk factor for systemic lupus erythematosus (SLE) flare. Two serotonin-related gene polymorphisms, the serotonin receptor 1A (5-HT1A) polymorphism at ,1019C>G and the serotonin transporter LS polymorphism, have been reported to affect stress-related behaviors. The purpose of this study was to assess the relationship between self-perceived stress (SPS), variability in SPS, and the 2 serotonin-related gene polymorphisms as risk factors for SLE flare. Methods Seventy-seven SLE patients (50 with lupus nephritis) were evaluated every 2 months (mean ± SD total followup 18.5 ± 8.5 months), and patients recorded their daily SPS levels (0,10 scale). Values for mean SPS and coefficient of variation (CV) for SPS were calculated from the 60-day block of daily measurements between study visits. Serotonin-related gene polymorphism genotypes were determined by polymerase chain reaction,based methods. Results Of the 77 patients, 53 experienced 80 flares of SLE (32 renal flares) based on prespecified criteria. Multivariate analysis revealed that whereas neither the serotonin-related gene polymorphisms nor the mean SPS was predictive of an SLE flare, an increased CV for SPS was predictive (P = 0.0031). Interaction between the CV for SPS and the 5-HT1A ,1019C>G polymorphism was also found to be a predictor of SLE flare (P = 0.0039). Subset analysis revealed that only in lupus nephritis patients were increasing CVs for SPS (P = 0.0002) and the interaction between CVs for SPS and 5-HT1A (P < 0.0001) predictive of a flare. Odds ratio curves demonstrated that the predictive effect of increasing CVs for SPS required the presence of the 5-HT1A ,1019 G allele, but appeared to be independent of the G allele number. Conclusion Fluctuation in the level of SPS is a risk factor for the onset of flare in SLE patients with major renal manifestations when it occurs on the background of a stress-related susceptibility gene (the 5-HT1A ,1019 G allele). [source] Electron Fluctuation in Pericyclic and Pseudopericyclic ReactionsCHEMPHYSCHEM, Issue 1 2006Eduard Matito Borderline cases: Differentiating between pericyclic and pseudopericyclic reactions is controversial. The authors analyze the electron distribution of the transition state of some known and some controversial reactions by means of the electron localization function (ELF) to elucidate their mechanism (see figure). This analysis provides a definitive criterion to distinguish between both electrocyclic processes. [source] Creating Value Through Corporate GovernanceCORPORATE GOVERNANCE, Issue 3 2002Robert A.G. Monks Value and governance are such familiar words that we do not often enough reflect on their meanings in a specific situation. This paper will suggest: Value is in the eye of the beholder. The appearance of governance may be preferable to the real thing. In order better to understand value, we will work with a simple question , is it appropriate for a global investor to purchase common shares in Volkswagen? There are many kinds of shareholder, each with distinctive interests that are not always compatible with the interests of the other investors. A global investor is typically the trustee of a pension plan with the simple obligation to collateralise the pension promise by maximising the long,term value of trust assets. The beneficiaries of pension funds are not rich people. Fluctuations in market values are no longer primarily a question as to whether rich people are a bit richer or poorer, they are a question as to whether pensions will be paid to the roughly half of the population of the OECD world who have interests in employee benefit plans. This makes investment a matter of social and political concern. At the end of our trip through the mythology and prospects for adding value to corporate enterprises through effective governance, we come to a very simple conclusion. I bastardise a celebrated principal of physics to conclude that both in science and in business a watched particle behaves differently than one that is not watched. "An observed board behaves differently" and is more likely to generate value for corporate owners. [source] Market Sentiment and Macroeconomic Fluctuations under Pegged Exchange RatesECONOMICA, Issue 292 2006PIERRE-RICHARD AGÉNOR The effects of an adverse change in market sentiment, defined as a temporary increase in the premium faced by domestic borrowers on world financial markets, are studied in an intertemporal optimizing framework with imperfect capital mobility. Firms' demands for working capital are financed by bank credit. The shock leads to a rise in domestic interest rates, capital outflows and a drop in official reserves, a reduction in bank deposits and loans, a contraction in output, and an increase in unemployment. These predictions are consistent with Argentina's economic downturn in the immediate aftermath of the Mexican peso crisis of December 1994. [source] Firing Costs, Employment Fluctuations and Average Employment: An Examination of GermanyECONOMICA, Issue 266 2000Jennifer Hunt West Germany's Employment Promotion Act of 1985 facilitated the use of fixed-term contracts and increased the number of dismissals above which the employer is required to establish a ,social plan' (involving severance payments). I assess the effect of this reduction in ,firing costs' on movements in employment, using monthly data on a panel of detailed manufacturing industries for 1977-92. I also examine the effect of introducing flexible hours of work in certain industries beginning in 1985. I find that employment adjustment was unaffected by the lower firing costs, but slowed by the greater working hours flexibility. [source] Variations in carotid arterial compliance during the menstrual cycle in young womenEXPERIMENTAL PHYSIOLOGY, Issue 2 2006Koichiro Hayashi The effect of menstrual cycle phase on arterial elasticity is controversial. In 10 healthy women (20.6 ± 1.5 years old, mean ±s.d.), we investigated the variations in central and peripheral arterial elasticity, blood pressure (carotid and brachial), carotid intima,media thickness (IMT), and serum oestradiol and progesterone concentrations at five points in the menstrual cycle (menstrual, M; follicular, F; ovulatory, O; early luteal, EL; and late luteal, LL). Carotid arterial compliance (simultaneous ultrasound and applanation tonometry) varied cyclically, with significant increases from the values seen in M (0.164 ± 0.036 mm2 mmHg,1) and F (0.171 ± 0.029 mm2 mmHg,1) to that seen in the O phase (0.184 ± 0.029 mm2 mmHg,1). Sharp declines were observed in the EL (0.150 ± 0.033 mm2 mmHg,1) and LL phases (0.147 ± 0.026 mm2 mmHg,1; F= 8.51, P < 0.05). Pulse wave velocity in the leg (i.e. peripheral arterial stiffness) did not exhibit any significant changes. Fluctuations in carotid arterial elasticity correlated with the balance between oestradiol and progesterone concentrations. No significant changes were found in carotid and brachial blood pressures, carotid artery lumen diameter, or IMT throughout the menstrual cycle. These data provide evidence that the elastic properties of central, but not peripheral, arteries fluctuate significantly with the phases of the menstrual cycle. [source] Dimensions of Ambiguous Loss in Couples Coping With Mild Cognitive Impairment,FAMILY RELATIONS, Issue 2 2007Rosemary Blieszner Abstract: We applied the theory of ambiguous loss to couples with mild cognitive impairment (MCI), an age-related decline in memory and other cognitive processes assumed not to interfere with daily activities or the maintenance of personal relationships. Face-to-face interviews with 67 older married couples revealed that lack of understanding about the behavioral manifestations of MCI resulted in much ambiguity in their lives. Fluctuations in the elders' functioning required spouses to alter their daily activities and responsibilities. As a result, couples often experienced distress that affected their emotional involvement with one another. Findings advance theoretical implications of ambiguous loss and provide educators and practitioners with suggestions for working with couples experiencing mild memory loss. [source] Fluctuations in European eel (Anguilla anguilla) recruitment resulting from environmental changes in the Sargasso SeaFISHERIES OCEANOGRAPHY, Issue 1 2008SYLVAIN BONHOMMEAU Abstract European eel decline is now widely observed and involves a large number of factors such as overfishing, pollution, habitat loss, dam construction, river obstruction, parasitism and environmental changes. In the present study, we analyzed the influence of environmental conditions in the Sargasso Sea and Atlantic ocean circulation on European glass eel recruitment success. Over a recent 11-yr period, we showed a strong positive correlation between an original index of glass eel recruitment and primary production (PP) in eel spawning area. Moreover, PP was negatively correlated with temperature in the Sargasso Sea. Therefore, we used sea temperature as an inverse proxy of marine production. A close negative relationship has been found over the last four decades between long-term fluctuations in recruitment and in sea temperature. These findings were reinforced by the detection of a regime shift in sea temperature that preceded the start of the decline in glass eel recruitment in the early 1980s. By contrast, variations in integrative indices measuring ocean circulation, i.e. latitude and strength of the Gulf Stream, did not seem to explain variations in glass eel recruitment. Our results support the hypothesis of a strong bottom-up control of leptocephali survival and growth by PP in the Sargasso Sea on short and long time scales. We argue that sea warming in the eel spawning area since the early 1980s has modified marine production and eventually affected the survival rate of European eels at early life stages. [source] Growth rates of phytoplankton under fluctuating lightFRESHWATER BIOLOGY, Issue 2 2000Elena Litchman Summary 1The effect of light fluctuations on the growth rates of four species of freshwater phytoplankton was investigated. Experimental light regimes included constant irradiance and fluctuations of a step function form, with equal proportion of high (maximum of 240 µmol photons m -2 s -1) and low light (minimum of 5 µmol photons m -2 s -1) (or dark) in a period. Fluctuations of 1, 8 and 24-h periods were imposed over several average irradiances (25, 50, 100 and 120 µmol photons m -2 s -1). 2Growth rate responses to fluctuations were species-specific and depended on both the average irradiance and the period of fluctuations. Fluctuations at low average irradiances slightly increased growth rate of the diatom Nitzschia sp. and depressed growth of the cyanobacterium Phormidium luridum and the green alga Sphaerocystis schroeteri compared to a constant irradiance. 3Fluctuations at higher average irradiance did not have a significant effect on the growth rates of Nitzschia sp. and Sphaerocystis schroeteri (fluctuations around saturating irradiances) and slightly increased the growth rates of the cyanobacteria Anabaena flos-aquae and Phormidium luridum (when irradiance fluctuated between limiting and inhibiting levels). 4In general, the effect of fluctuations tended to be greater when irradiance fluctuated between limiting and saturating or inhibiting levels of a species growth-irradiance curve compared to fluctuations within a single region of the curve. 5The growth rates of species under fluctuating light could not always be predicted from their growth-irradiance curves obtained under constant irradiance. When fluctuations occur between limiting and saturating or inhibiting irradiances for the alga and when the period of fluctuations is long (greater than 8 h), steady-state growth-irradiance curves may be insufficient to predict growth rates adequately. Consequently, additional data on physiological acclimation, such as changes in photosynthetic parameters, may be required for predictions under non-constant light supply in comparison to constant conditions. [source] Exploratory Analysis of Similarities in Solar Cycle Magnetic Phases with Southern Oscillation Index Fluctuations in Eastern AustraliaGEOGRAPHICAL RESEARCH, Issue 4 2008ROBERT G.V. BAKER Abstract There is growing interest in the role that the Sun's magnetic field has on weather and climatic parameters, particularly the ~11 year sunspot (Schwab) cycle, the ~22 yr magnetic field (Hale) cycle and the ~88 yr (Gleissberg) cycle. These cycles and the derivative harmonics are part of the peculiar periodic behaviour of the solar magnetic field. Using data from 1876 to the present, the exploratory analysis suggests that when the Sun's South Pole is positive in the Hale Cycle, the likelihood of strongly positive and negative Southern Oscillation Index (SOI) values increase after certain phases in the cyclic ~22 yr solar magnetic field. The SOI is also shown to track the pairing of sunspot cycles in ~88 yr periods. This coupling of odd cycles, 23,15, 21,13 and 19,11, produces an apparently close charting in positive and negative SOI fluctuations for each grouping. This Gleissberg effect is also apparent for the southern hemisphere rainfall anomaly. Over the last decade, the SOI and rainfall fluctuations have been tracking similar values to that recorded in Cycle 15 (1914,1924). This discovery has important implications for future drought predictions in Australia and in countries in the northern and southern hemispheres which have been shown to be influenced by the sunspot cycle. Further, it provides a benchmark for long-term SOI behaviour. [source] Money Market Uncertainty and Retail Interest Rate Fluctuations: A Cross-Country ComparisonGERMAN ECONOMIC REVIEW, Issue 2 2009Burkhard Raunig Interest rate pass-through; relationship banking; conditional volatility Abstract. This paper analyzes empirically the relationship between money market uncertainty and unexpected deviations in retail interest rates in a sample of ten OECD countries. We find that, with the exception of the United States, money market uncertainty has only a modest impact on the conditional volatility of retail interest rates. Even for the United States, we find that the effects of money market uncertainty are spread out over time. Our results also indicate that money market uncertainty tends to be passed on to retail rates to a lesser extent in countries where banking relationships play a substantial role. [source] Fluctuations of Vanessa cardui butterfly abundance with El Niño and Pacific Decadal Oscillation climatic variablesGLOBAL CHANGE BIOLOGY, Issue 5 2003ROBERT VANDENBOSCH Abstract Annual 4th of July Butterfly Count data spanning more than 20 years are examined to explore Vanessa cardui (Painted Lady) population fluctuations with ENSO (El Niño) and Pacific Decadal Oscillation (PDO) indices. California, Colorado and Nebraska censuses exhibit a strong positive correlation with the strong El Niño events of 1982,1983 and 1997,1998 and the weaker event of 1991,1992. Regression analysis shows the population fluctuations are strongly coupled to climate variations on both short (El Niño) and longer (Pacific Decadal Oscillation) time scales. Recognizing the sensitivity to these time scales is important for predicting longer-term global climate change effects. [source] Caliber Fluctuations of Cervical Internal Carotid Artery and Migraine With Aura: A Possible Vasospasm Detected by Ultrasonographic ExaminationsHEADACHE, Issue 7 2009Susanna Usai MD Caliber fluctuations of extra- and intracranial arteries, mostly related to vasospasm, are often recognized in various neurological conditions. We report a case of a 33-year-old woman affected by migraine with and without aura who exhibited a possible cervical internal carotid artery vasospasm, detected by ultrasound, before a typical migraine aura. [source] Active Crohn's disease and ulcerative colitis can be specifically diagnosed and monitored based on the biostructure of the fecal floraINFLAMMATORY BOWEL DISEASES, Issue 2 2008Alexander Swidsinski MD Abstract Background: The intestinal microflora is important in the pathogenesis of inflammatory bowel disease (IBD). The impact of its spatial organization on health and disease is unknown. Methods: We investigated sections of paraffin-embedded punched fecal cylinders. Fluctuations in spatial distribution of 11 bacterial groups were monitored in healthy subjects (n = 32), patients with IBD (n = 204), and other gastrointestinal diseases (n = 186) using fluorescence in situ hybridization (FISH). Results: The microbial structure differed in patients with Crohn's disease (CD), ulcerative colitis (UC), and healthy and disease controls. The profiles of CD and UC were distinctly opposite in 6 of 11 FISH probes used. Most prominent were a depletion of Faecalibacterium prausnitzii (Fprau<1 × 109/mL) with a normal leukocyte count in CD and a massive increase of leukocytes in the fecal-mucus transition zone (>30 leukocytes/104,m2) with high Fprau in patients with UC. These 2 features alone enabled the recognition of active CD (Crohn's Disease Activity Index [CDAI] >150) or UC (Clinical Activity Index [CAI] >3) with 79%/80% sensitivity and 98%/100% specificity. The mismatch in the sensitivity was mainly due to overlap between single IBD entities, and the specificity was exclusively due to the similarity of Crohn's and celiac disease. When inflammatory bowel disease (IBD) patients were pooled the sensitivity was 100% for severe disease, 84% for moderate activity, 72% for IBD with ,12 months remission, and 24% for IBD with >12 months remission. Conclusions: The fecal flora is highly structured and spatially organized. Diagnosing IBD and monitoring disease activity can be performed based on analysis of punched fecal cylinders independent from the patient's complaints. (Inflamm Bowel Dis 2007) [source] What Can Account for Fluctuations in the Terms of Trade?,INTERNATIONAL FINANCE, Issue 1 2006Marianne Baxter This paper studies the sources of terms of trade volatility. We decompose the terms of trade into two components. The ,goods price' component stems from differences in the composition of import and export baskets, while the ,country price' component stems from deviations from the law of one price. Countries are classified according to their major import and export goods: commodities, manufactured goods and fuels. Except fuel exporters, there is roughly equal importance of goods price vs country price volatility. These results suggest that there may be a role for reducing terms of trade volatility through diversification of a country's exports. [source] Global analysis of runs of annual precipitation and runoff equal to or below the median: run magnitude and severityINTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 5 2005Murray C. Peel Abstract Fluctuations of wet and dry years have long been investigated in the climatology and hydrology literature. In this, the second of two papers investigating runs of consecutive dry years, the magnitude, also known as the intensity, and severity (length × magnitude) of dry runs are investigated. In the first paper the length of dry runs was investigated. Periods of consecutive dry years are associated with drought and the attendant physical and economic stresses that are placed on society. Run magnitudes of consecutive years equal to or below the median were analysed for 3863 precipitation and 1236 runoff stations from around the world. For both annual precipitation and runoff, run magnitude was found to be predominately related to interannual variability and to a lesser extent skewness. Run magnitude of annual runoff was observed to be greater than that for annual precipitation, due to annual runoff having a higher coefficient of variation than annual precipitation. Continental differences in run magnitude of annual runoff were observed and were consistent with continental differences in interannual variability reported previously. Annual run severity was also investigated and found to be independent of run length and strongly related to run magnitude. These findings differ from previously published work; this difference is primarily due to the methodology of comparing run metrics between stations (used in this paper) rather than at a station (previous research). The relationships between run magnitude, severity and interannual variability highlight the importance of adequately reproducing interannual variability within global climate models for future modelling of drought scenarios, as well as having economic implications for drought relief and management policy-making. Copyright © 2005 Royal Meteorological Society. [source] Effect of systemic hormonal cyclicity on skinINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 1 2006N. Muizzuddin Fluctuations in estrogen and progesterone during the menstrual cycle can cause changes in body systems other than the reproductive system. We conducted several studies to determine a possible correlation between phases of the menstrual cycle and specific skin properties. Healthy Caucasian women (ages 21,48), who had a typical 26,29 day menstrual cycle, participated in the studies. Measurements of skin barrier strength, dryness, response to lactic acid stinging, skin surface lipids, and microflora were obtained every week for 2 to 3 months. Ultraviolet B (UV-B) susceptibility in terms of minimal erythemal dose was also studied. The skin barrier was the weakest between days 22 and 26 of the cycle. Elevated neuronal response (lactic acid sting) was not observed to vary much with the cycle. Skin was driest between day 1 and day 6, while skin surface lipid secretion appeared to be highest on days 16,20 of the hormonal cycle. The highest microbial count was around days 16,22, and there was a high UV-B susceptibility between days 20 and 28 of the menstrual cycle. [source] Atlantic reef fish biogeography and evolutionJOURNAL OF BIOGEOGRAPHY, Issue 1 2008S. R. Floeter Abstract Aim, To understand why and when areas of endemism (provinces) of the tropical Atlantic Ocean were formed, how they relate to each other, and what processes have contributed to faunal enrichment. Location, Atlantic Ocean. Methods, The distributions of 2605 species of reef fishes were compiled for 25 areas of the Atlantic and southern Africa. Maximum-parsimony and distance analyses were employed to investigate biogeographical relationships among those areas. A collection of 26 phylogenies of various Atlantic reef fish taxa was used to assess patterns of origin and diversification relative to evolutionary scenarios based on spatio-temporal sequences of species splitting produced by geological and palaeoceanographic events. We present data on faunal (species and genera) richness, endemism patterns, diversity buildup (i.e. speciation processes), and evaluate the operation of the main biogeographical barriers and/or filters. Results, Phylogenetic (proportion of sister species) and distributional (number of shared species) patterns are generally concordant with recognized biogeographical provinces in the Atlantic. The highly uneven distribution of species in certain genera appears to be related to their origin, with highest species richness in areas with the greatest phylogenetic depth. Diversity buildup in Atlantic reef fishes involved (1) diversification within each province, (2) isolation as a result of biogeographical barriers, and (3) stochastic accretion by means of dispersal between provinces. The timing of divergence events is not concordant among taxonomic groups. The three soft (non-terrestrial) inter-regional barriers (mid-Atlantic, Amazon, and Benguela) clearly act as ,filters' by restricting dispersal but at the same time allowing occasional crossings that apparently lead to the establishment of new populations and species. Fluctuations in the effectiveness of the filters, combined with ecological differences among provinces, apparently provide a mechanism for much of the recent diversification of reef fishes in the Atlantic. Main conclusions, Our data set indicates that both historical events (e.g. Tethys closure) and relatively recent dispersal (with or without further speciation) have had a strong influence on Atlantic tropical marine biodiversity and have contributed to the biogeographical patterns we observe today; however, examples of the latter process outnumber those of the former. [source] | |||||||||||||||||||||||||||||||||||||